JEFFERSON COUNTY, Colo. (CBS4) – Trails at the new Rocky Flats National Wildlife Refuge officially open to the public this weekend in Jefferson County.

CBS4 reported last week, one trail head is already open.

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(CBS)

The superfund site has been off limits for years. It was once a government facility to build parts for nuclear weapons during the Cold War.

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(CBS)

Environmentalists sued to stop the trails from opening, saying they are unsafe.

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Officials say the land is clean and safe for hikers and bikers to enjoy.